Wrist arthroplasty system and method

Abstract

The present disclosure provides for a wrist arthroplasty system and method that enable an expedient surgical procedure, maintain wrist motion, and reduce the likelihood of implant loosening. The system includes a capitate implant, a radial implant, and a resection instrument. The capitate implant includes a convex head formed to interface with a concave socket of the radial implant. The capitate implant includes a single stem formed to be secured within a patient's capitate bone. The radial implant includes lips formed to increase wrist joint motion and to help prevent dislocation of the capitate implant from the radial implant. The resection instrument may be used in combination as a measurement tool for determining the proper implant size, a guide for properly positioning the implants, and a trial tool for testing trial implant components before securing the final radial and capitate implants.

The invention claimed is: 
     
       1. A wrist arthroplasty system comprising:
 a capitate implant including a capitate stem extending from a carpal surface of a head portion, wherein the head portion includes a convex surface opposite the carpal surface; 
 a radial implant including:
 a base component, 
 a radial stem extending from a first side of the base component, and 
 a socket extending from a second side of the base component opposite the first side, wherein the socket includes two lips forming a concave opening adapted to interface with the convex surface of the capitate implant; and 
 
 a resection instrument including:
 a distal radius guide including a trial socket formed integrally with a reaming guide, wherein the trial socket is configured to substantially replicate the socket of the radial implant, and wherein the reaming guide includes an opening sized according to the trial socket, 
 a guide block including a plurality of holes each adapted respectively to receive a fixture instrument, wherein the guide block is configured to receive a depth control instrument, and 
 the depth control instrument including an adjustment knob, wherein the depth control instrument is configured to removably engage with the guide block such that, when engaged, rotating the adjustment knob causes the depth control instrument to translate relative to the guide block. 
 
 
     
     
       2. The system of  claim 1 , wherein the convex surface of the capitate implant includes a curvature adapted to replicate a surface of a lunate facet nearest a distal surface of a radius bone. 
     
     
       3. The system of  claim 1 , wherein the capitate implant includes a cobalt chromium alloy. 
     
     
       4. The system of  claim 1 , wherein the radial implant includes a titanium alloy. 
     
     
       5. The system of  claim 1 , wherein the socket includes high molecular weight polyethylene. 
     
     
       6. The system of  claim 1 , wherein the distal radius guide is removably secured to the guide block. 
     
     
       7. The system of  claim 1 , wherein the resection instrument includes a set of distal radius guides, wherein each respective distal radius guide of the set of distal radius guides includes a trial socket of a different size. 
     
     
       8. The system of  claim 7 , further comprising a set of reamers, wherein each respective reamer of the set of reamers corresponds to a respective distal radius guide of the set of distal radius guides. 
     
     
       9. The system of  claim 1 , wherein the depth control instrument includes a threaded leg and an indicator leg including a plurality of indicators, and wherein the threaded leg is configured to engage with the guide block such that rotating the adjustment knob causes the depth control instrument to translate relative to the guide block.